This project is directed toward the development of a simple and reliable technique to both spatially and temporally control the photoactivating pulsed red beam while imaging with either low intensity pulsed red light (i.e. TPLSM) or with an argon laser (CLSM). A simple solution we have devised is the use of one scanner and a programmable counter circuit to count the pixel and line sync pulses and then trigger a Pockels cell at the correct time, allowing a pulse of photoactivating laser light to hit the sample. This arrangement allows for the continuous acquisition of images while repeatedly uncaging bioeffector molecules at selected coordinates within the image field.